Test for STDDEV_POP(), STDDEV_SAMP(), VAR_POP() and VAR_SAMP() functions with Firebird3

test_stddev_fb.py

# coding:utf-8

import unittest
import tempfile
import firebirdsql

class TestStdDev(unittest.TestCase):
    host='localhost'
    port=3050
    user='sysdba'
    password='masterkey'
    def setUp(self):
        self.database=tempfile.mktemp()
        self.connection = firebirdsql.create_database(
                host=self.host,
                port=self.port,
                database=self.database,
                user=self.user,
                password=self.password)

        cur = self.connection.cursor()
        cur.execute("""
            create table test_stddev (
                i integer,
                d double precision
            )
        """)
        self.connection.commit()

        self.connection.begin()
        cur = self.connection.cursor()
        for i in range(10):
            cur.execute("insert into test_stddev (i, d) values (?, ?)", (i+1, i+1))

        self.connection.commit()

    def tearDown(self):
        self.connection.close()

    def test_stddev_pop(self):
        cur = self.connection.cursor()
        cur.execute("select stddev_pop(d) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 2.8722813232690143)
        cur.execute("select stddev_pop(i) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 2.8722813232690143)

    def test_stddev_samp(self):
        cur = self.connection.cursor()
        cur.execute("select stddev_samp(d) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 3.0276503540974917)
        cur.execute("select stddev_samp(i) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 3.0276503540974917)

    def test_var_pop(self):
        cur = self.connection.cursor()
        cur.execute("select var_pop(d) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 8.25)
        cur.execute("select var_pop(i) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 8.25)

    def test_var_samp(self):
        cur = self.connection.cursor()
        cur.execute("select var_samp(d) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 9.166666666666666)
        cur.execute("select var_samp(i) from test_stddev")
        self.assertEqual(cur.fetchone()[0], 9.166666666666666)

if __name__ == "__main__":
    unittest.main()